The present invention relates to a projection equipment in which a high-pressure discharge lamp such as a high-pressure mercury lamp is used as a light source lamp, and a method of driving the light source lamp in the projection equipment, and a program thereof.
In recent years, a technology has been proposed, which controls a release voltage for the purpose of preventing discharge at the root of electrode of the high-pressure discharge lamp used as the light source lamp in a projector equipment at the time of starting operation, whereby the release voltage does not rise even though an input voltage increases at the time of starting operation of the high-pressure discharge lamp, and whereby even through a glow discharge produced by starting pulses is released from the root of the cathode electrode of the high-pressure discharge lamp to an inner wall of the lamp tube, an arc transfer does not occur. As a result, damage to the lamp due to the discharge from the electrode root is prevented, and also optical displacement, as well as variations in a lamp voltage and change in color are avoided. For example, refer to Patent Document #1.
[Patent Document #1] Japanese Laid-open Patent Specification No. 1997-069394
The technology disclosed in the Patent Document #1 prevents discharge at the electrode root of the lamp and instantly turns on the lamp when the power is recovered from the accident where the high-pressure discharge lamp serving as the light source lamp is abruptly turned off due to some reasons, for example, where the lamp is abruptly turned off because the electric code is pulled out by mistake.
However, the high-pressure discharge lamp heated to more than some temperature cannot be always turned on again when the starting pulses are applied thereto, and even if a user tries to apply a necessary voltage to the lamp several times to turn on same, the high-pressure discharge lamp often fails to turn on. In this case, the electrodes of the high-pressure lamp deteriorates seriously and its operational lifetime decreases.